#include <stdio.h>
#define NUM 8
int a[NUM+1];
main()
{
    int number, i,k,flag,not_finish=1,count=0;
     i=1;
     a[1]=1;
     printf("The possible configuration of 8 queens are:\n");
     while (not_finish)
     {
        while (not_finish && i<=NUM)
        {
            for (flag=1,k=1;flag && k<i;k++)
              if (a[k]==a[i]) flag=0;
            for(k=1;flag && k<i;k++)
              if (( a[i]==a[k]-(k-i)) || (a[i]==a[k]+(k-i)) ) flag=0;
                if ( !flag)
                {
                    if(a[i]==a[i-1])
                    {
                        i--;
                        if(i>1 && a[i]==NUM)
                                a[i]=1;
                        else if(i==1 && a[i]==NUM)
                                not_finish=0;
                        else a[i]++;
                    }
                    else if (a[i]==NUM) a[i]=1;
                    else a[i]++;
                }
                else if ( ++i<=NUM )
                       if(a[i-1]==NUM) a[i]=1;
       
                       else a[i]=a[i-1]+1;
        }
        if (not_finish)
        {
            ++count;
            
            printf( (count-1)%3 ? "[%2d]:" : "\n[%2d]:",count);
            for (k=1;k<=NUM;k++)
              printf(" %d",a[k]);
            if(a[NUM-1]<NUM) a[NUM-1]++;
            else a[NUM-1]=1;
            i=NUM-1;
        }
     
     }
}
